A resilience assessment methodology for urban drainage systems considering the influence of structural factors

Abstract

[Objective] Frequent global flooding has led to increasing challenges for urban drainage systems, including not only extreme rainfall, but also the uncertain threats posed by potential structural failures such as pipe deterioration and bursting. In order to study the level of resilience of urban drainage systems under extreme external rainfall and internal structural failure, [Methods] considering the influence of pipe age and flow velocity, the structural failure probability calculation method is proposed, and the overloading scenario without considering structural factors and the composite scenario with considering structural factors are constructed. Based on the comprehensive consideration of the preparatory stage, response stage and recovery stage of the response process of urban drainage system to extreme loads, the resilience assessment indexes are selected and a resilience assessment model based on cloud model is established. The proposed method is applied to the study area for case study analysis. [Results] The result show that the total flood volume in the urban drainage system under the composite scenario increased by more than 60% compared with the exceeding load scenario, and the average flood duration increased by more than 1.0 h. After topology optimization, the total flood volume in the urban drainage system under the exceeding load scenario and the composite scenario decreased by 24.7%~30.1% and 20.5%~48.4%, respectively. [Conclusion] Structural failure has a certain impact on the resilience of urban drainage systems, leading to a decrease in drainage capacity; topology optimization can improve the system resilience to a certain extent. The result show that the proposed method can effectively assess the resilience of urban drainage systems under extreme loads and provide a reference for the safe operation of urban drainage systems under extreme loads.

Keywords

urban drainage systems / structural factors / extreme loads / resilience assessment / climate change / flood / rainfall / extreme weather